Koi Angelfish Not Eating

[Ali448]

My 4 yr old Koi Angel isn't eating. Night before last he looked really sick at the bottom of the 55g tank. The next morning he was swimming okay but staying low in the water and not coming up to the top at feeding time. Today he's still not eating. He tried at particles floating by, but spit out the one bite he took. I don't see any physical symtoms.
All the tank parameters are in healthy range and other fish are fine. This tank has been in operation for over 20 years.
I'm baffled. Please help.

 

[Andy Sager]

My 4 yr old Koi Angel isn't eating. Night before last he looked really sick at the bottom of the 55g tank. The next morning he was swimming okay but staying low in the water and not coming up to the top at feeding time. Today he's still not eating. He tried at particles floating by, but spit out the one bite he took. I don't see any physical symtoms.
All the tank parameters are in healthy range and other fish are fine. This tank has been in operation for over 20 years.
I'm baffled. Please help.

Could be old age or it could be an internal issue. There's another aspect to consider, Koi Angelfish are a mixture of 7 different lines of Angelfish so they are literally a genetic soup of genes which could play big on their lifespans. While you will see many sites exclaiming how Angels can live 10-12 years or longer, those stats are really for most of the color forms that are closer to wild so they have less diffused genetics.

Other things to consider: Have you added any new fish lately?
Is this the only Angelfish in the tank?
What is the general diet the fish has been eating?
Do you see any aggression between this fish and any other fish in the tank that could cause depression in this fish?
Do you see any white discharge from the fish's anus?

As for what I would do: I would place this fish into a hospital tank, alone, and treat the water with Epsom salt ( 1 teaspoon per gallon of water) and observe for 2 days. This is to see if there is any bloating developing or possibly some intestinal blockage that the fish is having a hard time passing. If no difference, I would consider treating the fish with Kanaplex if your water Ph is above 7.0 or nalidixic acid or minocycline if the Ph is below 6.9 and your GH is low. ( High GH will counter the therapeutic effects of nalidixic acid.)

Hope this helps.

 

[Ali448]

Thank you so much. The pH is 7.0. He's the only angel and no new fish have been added. I haven't made any dietary changes.
I have noticed his left gill isn't moving much, but there's no external damage. I haven't seen any discharge, but I'll get him in isolation and watch for it.
Thanks again.

 

[Andy Sager]

Thank you so much. The pH is 7.0. He's the only angel and no new fish have been added. I haven't made any dietary changes.
I have noticed his left gill isn't moving much, but there's no external damage. I haven't seen any discharge, but I'll get him in isolation and watch for it.
Thanks again.

Have you seen him scratching or flashing that side of his face?